Bug in lmt_arrow
Hi, There is a bug in lmt_arrow. If given a "non-cycle" path, lmt_arrow completes the cycle. \starttext \startMPcode newpath p; ahfactor := 5; p := origin .. (1cm, 1cm) .. (2cm, 0); draw lmt_arrow [ path = p, location = "percentage", percentage = 50, alternative = "curved", ] withpen pencircle scaled 1bp; \stopMPcode \stoptext With 2021.11.11, I get the attached file. Note that lmt_arrow has drawn the "cycle" version of the path, even though p does not have a cycle. I have looked at the code and cannot figure out why this is happening. Thanks, Aditya
On 11/14/2021 4:33 AM, Aditya Mahajan via ntg-context wrote:
it happens in the 'direct' variant (metapost.registerdirect) where a boolean is passed as signal and that boolean then is also picked up by the (shared) path injector as (old school) signal that a path is closed while it should instead consutl the closed field in a path table (sounds more complex than it is) so in the end it is a nasty side effect of the fast inject code path (shared function with different stack values; i'll probably have to ditch a "low level backward compatibility feature no one uses anyway" some day) i uploaded a fix that you can test when the bins are compiled at https://build.contextgarden.net/#/waterfall?tags=c.luametatex new bins then in: https://dl.contextgarden.net/build/luametatex/ (fyi: in the mp code you see that the path p is 'get' from the lua end where it got passed to by parameter) (interesting that it didn't show up sooner, maybe most users have closed paths and/or most lmt_ features used closed paths) Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------
On Sun, 14 Nov 2021, Hans Hagen wrote:
Thanks! Works perfectly here.
(interesting that it didn't show up sooner, maybe most users have closed paths and/or most lmt_ features used closed paths)
I was reusing two year old code and took me a while to figure out why the output was suddenly wrong. Aditya
On Sun, 14 Nov 2021, Aditya Mahajan via ntg-context wrote:
Spoke too soon. Now straight lines don't work: \starttext \startMPcode newpath p; ahfactor := 5; p := origin .. (3cm,0); draw lmt_arrow [ path = p, location = "percentage", percentage = 50, alternative = "curved", ] withpen pencircle scaled 1bp; \stopMPcode \stoptext gives metapost > trace > This is MPLIB for LuaMetaTeX, version 3.11, running in scaled mode. metapost > trace > metapost > trace > loading metafun for lmtx, including the plain 1.004 base definitions metapost > trace > metafun > log > metafun > log > error: This can't happen (division by zero) metafun > log > metapost > trace > <macro> arrowhead -> <expr> -> begingroup.save.q,e,r;pair.e;e=point.length(EXPR2)of(EXPR2);path.q;q=gobble((EXPR2)shifted-e.cutafter.makepath(pencircle.scaled(2ahlength)))cuttings;if.ahvariant>0:path.r;r=gobble((EXPR2)shifted-e.cutafter.makepath(pencircle.scaled((1-ahdimple)*2ahlength)))cuttings;fi(q.rotated(ahangle/2)&reverse.q.rotated-(ahangle/2)if.ahvariant=1:--point0of.r--elseif.ahvariant=2:...point0of.r...else:--fi.cycle)shifted.e.endgroup metapost > trace > <to be read again> endgroup metapost > trace > <argument> pushparameters "arrow" ; save a ; string a ; a := getparameter "alternative" ; save l ; string l ; l := getparameter "location" ; save k ; string k ; k := getparameter "kind" ; save p ; path p ; p := getparameter "path" ; interim ahvariant := if a = "dimpled" : 1 elseif a = "curved" : 2 else : 0 fi ; interim ahdimple := getparameter "dimple" ; interim ahscale := getparameter "scale" ; interim ahangle := getparameter "angle" ; interim ahlength := getparameter "length" ; if not getparameter "headonly" : draw p ; fi ; if hasparameter "pen" : if hasoption "pen" "auto" : ahlength := ( getparameter "penscale" ) * boundingradius ( currentpen ) ; else : ahlength := ( getparameter "penscale" ) * boundingradius ( getparameterpen "pen" ) ; fi ; fi ; if k = "draw" : draw elseif k = "both" : filldraw else : fill fi if l = "middle" : midarrowhead p ; elseif l = "percentage" : arrowheadonpath ( p , ( getparameter "percentage" ) / 100 ) ; elseif l = "both" : arrowhead p ; if k = "draw" : draw elseif k = "both" : filldraw else : fill fi arrowhead reverse p ; else : arrowhead p ; fi ; popparameters ; metapost > trace > <macro> image -> (TEXT3)-> begingroup.save.currentpicture;picture.currentpicture;currentpicture:=nullpicture;(TEXT3);currentpicture.if.str(SUFFIX2)<>"":shifted(mfun_labxf(SUFFIX2)*lrcorner.p+mfun_labyf(SUFFIX2)*ulcorner.p+(1-mfun_labxf(SUFFIX2)-mfun_labyf(SUFFIX2))*llcorner.p)fi.endgroup metapost > trace > <macro> lmt_do_arrow -> -> begingroup.image(pushparameters"arrow";save.a;string.a;a:=getparameter"alternative";save.l;string.l;l:=getparameter"location";save.k;string.k;k:=getparameter"kind";save.p;path.p;p:=getparameter"path";interim.ahvariant:=if.a="dimpled":1elseif.a="curved":2else:0fi;interim.ahdimple:=getparameter"dimple";interim.ahscale:=getparameter"scale";interim.ahangle:=getparameter"angle";interim.ahlength:=getparameter"length";if.not.getparameter"headonly":draw.p;fi;if.hasparameter"pen":if.hasoption"pen""auto":ahlength:=(getparameter"penscale")*boundingradius(currentpen);else:ahlength:=(getparameter"penscale")*boundingradius(getparameterpen"pen");fi;fi;if.k="draw":draw.elseif.k="both":filldraw.else:fill.fi.if.l="middle":midarrowhead.p;elseif.l="percentage":arrowheadonpath(p,(getparameter"percentage")/100);elseif.l="both":arrowhead.p;if.k="draw":draw.elseif.k="both":filldraw.else:fill.fi.arrowhead.reverse.p;else:arrowhead.p;fi;popparameters;)endgroup metapost > trace > <scantokens> lmt_do_arrow metafun > log > metafun > log > I'm broken. Please show this to someone who can fix can fix it and try again metafun > log > metapost > trace > <direct> newpath p; ahfactor := 5; p := origin .. (3cm,0); draw lmt_arrow [ path = p, location = "percentage", percentage = 50, alternative = "curved", ] withpen pencircle scaled 1bp; ; metapost > trace > Aditya
On 11/15/2021 4:07 AM, Aditya Mahajan wrote:
new attempt (submitted to build) ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------
On Mon, 15 Nov 2021, Hans Hagen wrote:
The following still fails with ver 2021.11.19 \starttext \startMPcode newpath p; ahfactor := 5; p := origin .. (3cm,0); draw lmt_arrow [ path = p, location = "percentage", percentage = 50, alternative = "curved", ] withpen pencircle scaled 1bp; \stopMPcode \stoptext I get an error: metafun > log > metafun > log > error: This can't happen (division by zero) metafun > log > Thanks, Aditya
On 11/20/2021 6:53 AM, Aditya Mahajan via ntg-context wrote:
Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------
participants (2)
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Aditya Mahajan -
Hans Hagen